Question

A physical pendulum consists of a spherical bob of radius rand
mass m suspended from a string. The distance from the center ofthe
sphere to the point of support is L. When r is much less thanL,
such a pendulum is often treated as a simple pendulum of
lengthL.

a) Show that the period for small oscillations is
givenby

, where is the period of a simple pendulum of length
L.(Well, this part I could solve it, it's not necessary to write
itfor me, thanks)... But I can't solve B and C:

b) Show that when r is much smaller than L, the period
isapproximately

c) If L = 1 m and r = 2 cm, find the error when
theapproximation T=T0 is used for this pendulum. How
largemust be the radius of the bob for the error to be 1% ?